(1) Field of the Invention
The present invention relates to a school satchel produced from several parts made of variable raw materials, the back wall of which is made of plastic and preferably is curved concavely in a transverse direction, fitting the body.
(2) Description of the Prior Art.
Most known school satchels, obtainable on the market and designed to rest on the back of the person carrying it, are relatively soft, whereby the amorphous, soft part of the back wall, which is not capable of elastically retaining any shape imparted to it, is anatomically unfavorable and is accompanied by puntiform pressure spots, so that these satchels are uncomfortable when carried on the back.
Mostly, the known school satchels consist of leather or material similar to leather, such as a soft plastic or synthetic leather. Apart from an indisputably low wear factor, and beside its softness, leather has the disadvantage of absorbing moisture relatively well and to be pervious to water, so that the contents of the school satchel in case of bad weather (snow or rain) are not protected absolutely against the action of moisture and, upon staying in said school satchel for a prolonged period of time, will infallibly be damaged. This hygroscopic characteristic of the leather makes cleaning problematical too. Furthermore, leather is very difficult to dye and also not very colorfast, and it also has a fairly high weight of its own.
From the German AS No. 1,297,292, furthermore, a school satchel has been known, which consists of a plastic container, formed in one piece, with a hinged cover attached to the container and consisting of leather or some similar raw material. At the same time the back wall of the container is adapted to the shape of the body so that carrying of this school satchel is made more easy.
The disadvantage in case of these known school satchels as well as in case of the above described, traditional school satchels especially is, that any true rationalization during finishing or pre-finishing is hardly possible. Rather a whole series of additional operations will be necessary during manufacture, which will have to be done mainly be skilled workers and by hand.
Furthermore, the known school satchels are relatively heavy because of the material used. As an example, the average weight of known school satchels amounts to 1 kg to about 1.20 kg, in extreme cases even 1.70 kg. That, measured by the weight of the books and teaching aids of a fourth grader, which amount to about 3.5 kg, already constitutes about half the weight of the articles to be carried. Beyond that, the known school satchels are also too large and cumbersome, i.e., the dimension of the school satchels do not correspond either to the body measurements of a child nor to the shape of the teaching aids carried. These reasons lead to the fact, that the school satchel always acts as a foreign body and is always felt to be tiresome and unpleasant.
Another disadvantage of the known school satchels is the fact that the cover is always placed over the feed opening from behind to the front, i.e., whenever the school satchel hangs or stands, always two manipulations are needed: the cover must be pulled up with one hand and must be held during the entire charging or removal process, while the other hand does the filling or removing. That means that the content of the school satchel cannot be inspected at just any time and only with a special effort. Moreover, in the case of empty or nearly empty school satchels the closing arrangement is often insufficient, since an escape of the satchel, whenever the cover is pressed against it, is unavoidable. In addition, generally simple metal spring locks are used for closing the school satchels, which are attached to the edge of the cover and the front of the school satchel. As a result of the inflexibility in direction of pull of the cover and of the front wall, and as a result of the type of construction of the closing arrangment, in most cases no possibility of adaptation of the volume of the satchel to the content is possible. If, in the extreme case, the satchel is empty or almost empty, i.e., if it has been charged with few contents, then the closing of the cover can be accomplished only with great difficulty because of a lacking counter pressure.